Conventionally, a door sash for accommodating an outer peripheral end part of a door glass is known. The door sash is a polygonal line-shaped frame fixed to a door body, and is manufactured by roll forming a band-shaped plate material.
For example, Patent Literature 1 discloses a door sash including: a tubular part formed in a D-shape in a cross-sectional view; an overlapping part extending from the tubular part; and design parts formed to respectively project from the overlapping part in the opposite lateral directions.
The overlapping part includes a first overlapping part in which the plate material is overlapped in two layers and a second overlapping part in which the plate material is overlapped in three layers. The second overlapping part is formed by further overlapping an end portion of the plate material onto the plate material (overlapped in two layers) extending from the first overlapping part.